Electrical Junction Box and Wire Harness

CROSS-REFERENCE TO RELATED APPLICATION(S)

The present application claims priority to and incorporates by reference the entire contents of Japanese Patent Application No. 2023-077799 filed in Japan on May 10, 2023.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electrical junction box and a wire harness.

2. Description of the Related Art

Conventionally, for example, JP 2021-052189 A discloses a configuration including: a relay and a bus bar as heat generating components; a cooling member that cools the relay and the bus bar; and a case made of resin that is a radiator and holds the relay, the bus bar, and the cooling member. The cooling member is formed by pressing a plate member made of metal into a substantially L shape. A heat conductive member made of resin is provided between the cooling member and the bottom face of the case.

In addition, conventionally, for example, JP 2020-127302 A discloses a configuration including: a relay and a bus bar as heat generating components; a heat transfer member that cools the bus bar; and a case that holds the relay, the bus bar, and the heat transfer member. The bus bar is formed in a substantially Z shape by providing a second portion extending in the up-down direction between a first portion and a third portion that extend in the same direction. The first portion is connected to the relay, and the third portion is connected to the heat transfer member.

Here, in order to improve the cooling performance, it is conceivable to increase the volume of the cooling member and the heat transfer member described above, but in this case, there are concerns about an increase in weight, an increase in size, and the like. Therefore, there is room for further improvement.

SUMMARY OF THE INVENTION

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electrical junction box and a wire harness that can appropriately have cooling performance.

To achieve the object of the present invention, a electrical junction box according to one aspect of the present invention includes a heat generating component; a cooling unit being configured to cool the heat generating component; and a resin case being configured to hold the heat generating component and the cooling unit, wherein the cooling unit includes a metal plate being formed in a shape conforming to a shape of the heat generating component, a metal pipe through which a coolant flows, the metal pipe being disposed along and in contact with the metal plate, and a heat transfer member having insulating properties and intervening between the heat generating component and the metal plate.

To achieve the object of the present invention, a wire harness according to another aspect of the present invention includes a wiring member having electrical conductivity; and an electrical junction box being electrically connected to the wiring member, wherein the electrical junction box includes a heat generating component, a cooling unit being configured to cool the heat generating component, and a resin case being configured to hold the heat generating component and the cooling unit, and the cooling unit includes a metal plate being formed in a shape conforming to a shape of the heat generating component, a metal pipe through which a coolant flows, the metal pipe being disposed along and in contact with the metal plate, and a heat transfer member having insulating properties and intervening between the heat generating component and the metal plate.

The above and other objects, features, advantages and technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an electrical junction box and a wire harness according to an embodiment;

FIG. 2 is a plan view of the electrical junction box according to the embodiment;

FIG. 3 is a perspective view of the electrical junction box according to the embodiment, excluding a resin case;

FIG. 4 is a sectional view taken along line A-A of FIG. 2 ; and

FIG. 5 is a sectional view taken along line B-B of FIG. 2 .

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the drawings. Note that this invention is not limited to the embodiment. Constituent elements in the following embodiment include those that can be easily replaced by a person skilled in the art or those that are substantially the same.

In the following description, three directions intersecting one another are referred to as a “length direction (first direction) X”, a “width direction (second direction) Y”, and a “height direction (third direction) Z” for convenience. Here, the length direction X, the width direction Y, and the height direction Z are orthogonal to one another. Typically, the length direction X and the width direction Y correspond to a horizontal direction (also referred to as a planar direction). Typically, the length direction X corresponds to a long side direction of an electrical junction box 10 , and the width direction Y corresponds to a short side direction of the electrical junction box 10 . Typically, the height direction Z corresponds to the vertical direction. A “vertically upper side”, “vertically upward”, or “vertically above” is referred to as an “upper portion”, an “upper side”, “upper”, “upward”, or “above”, and a “vertically lower side”, “vertically downward”, or “vertically below” is referred to as a “lower portion”, a “lower side”, “lower”, “downward”, or “below”.

The electrical junction box 10 of the embodiment is mounted on a vehicle such as an automobile and incorporated in a wire harness WH as illustrated in FIG. 1 . The wire harness WH is, for example, a member connects a plurality of wiring members W used for power supply and signal communication to devices mounted on a vehicle by a connector or the like to connect the devices to each other. The wire harness WH includes the wiring member W having electrical conductivity and the electrical junction box 10 electrically connected to the wiring member W. The wiring member W is formed of, for example, a metal rod, an electric wire, an electric wire bundle, or the like. The metal rod is formed by covering an outer side of an electrically conductive rod-shaped member with an insulating covering portion. The electric wire is formed by covering an outer side of a conductor (core wire) including a plurality of electrically conductive metal element wire with an insulating covering portion. The wire harness WH may further include a grommet, a protector, a fastener, and the like.

The electrical junction box 10 collectively houses therein electronic components such as a connector, a fuse, a relay, a capacitor, a branch portion, an electronic control unit, and an electronic component unit obtained by unitizing these components. The electrical junction box 10 is installed, for example, in an engine room of a vehicle or a vehicle cabin. The electrical junction box 10 is connected between a power supply such as a battery and various electronic devices mounted in the vehicle via the wiring member W or the like. The electrical junction box 10 distributes electric power supplied from a power supply to various electronic devices in the vehicle. The electrical junction box 10 may also be referred to as a junction box, a fuse box, a relay box, or the like, but these are collectively referred to as an electrical junction box in the present embodiment. In each drawing, a part of the electrical junction box 10 is taken out and schematically illustrated.

As illustrated in FIGS. 1 to 5 , the electrical junction box 10 of the embodiment includes a heat generating component 11 , a cooling unit 12 , and a resin case 13 .

The heat generating component 11 is a component that generates heat following energization. In the present embodiment, the heat generating component 11 is a relay 2 and a bus bar 3 . The heat generating component 11 may be an electronic component such as a connector, a fuse, a capacitor, a branch portion, an electronic control unit, or an electronic component unit obtained by unitizing these components.

The cooling unit 12 cools the heat generating component 11 . The cooling unit 12 includes a heat transfer member 4 , a metal plate 5 , and a metal pipe 6 .

The resin case 13 holds the heat generating component 11 and the cooling unit 12 .

Details of the electrical junction box 10 will be described below.

As illustrated in FIGS. 1 and 2 , the resin case 13 is formed of an insulating synthetic resin. The resin case 13 includes a base 13 a , a one end 13 b , and an other end 13 c.

The base 13 a is formed in a plate shape so as to have a predetermined width dimension in the width direction Y, a predetermined length dimension in the length direction X, and a height dimension in the height direction Z being constant over the width direction Y and the length direction X. The base 13 a includes an upper face 13 aa that is flat along a plane formed by the width direction Y and the length direction X in a face on the upper side in the height direction Z.

The one end 13 b is provided on one side of the base 13 a in the length direction X. The one end 13 b is formed integrally on one side of the base 13 a in the length direction X. The one end 13 b is formed on one side of the base 13 a in the length direction X so as to have the same dimension as the width dimension of the base 13 a in the width direction Y and to have a larger height dimension in the height direction Z. Specifically, the one end 13 b includes an upright face 13 ba rising upward from the upper face 13 aa of the base 13 a and being flat along a vertical plane formed by the width direction Y and the height direction Z. The one end 13 b includes a top face 13 bb that is continuous to the upper end of the upright face 13 ba and is parallel to the upper face 13 aa of the base 13 a . Therefore, the one end 13 b constitutes a step protruding upward in the height direction Z on one side of the base 13 a in the length direction X. The one end 13 b includes a cutout 13 bc that is recessed downward in the height direction Z in the top face 13 bb.

The other end 13 c is provided on the other side of the base 13 a in the length direction X. The other end 13 c is formed integrally on the other side of the base 13 a in the length direction X. The other end 13 c is formed on the other side of the base 13 a in the length direction X so as to have the same dimension as the width dimension of the base 13 a in the width direction Y and to have a larger height dimension in the height direction Z. Specifically, the other end 13 c includes a slope 13 ca rising obliquely upward from the upper face 13 aa of the base 13 a . The other end 13 c includes a top face 13 cb that is continuous to the upper end of the slope 13 ca and is parallel to the upper face 13 aa of the base 13 a . Therefore, the other end 13 c constitutes a step protruding upward in the height direction Z on the other side of the base 13 a in the length direction X. The other end 13 c includes a cutout 13 cc that is recessed downward in the height direction Z in the top face 13 cb.

As illustrated in FIGS. 1 and 2 , the relay 2 of the heat generating component 11 is disposed on the upper face 13 aa of the base 13 a in the resin case 13 and is fixed to the resin case 13 with a bolt 8 .

As illustrated in FIGS. 1 and 2 , the bus bar 3 of the heat generating component 11 includes a first bus bar 3 A and a second bus bar 3 B that are independently connected to the relay 2 .

The first bus bar 3 A is provided to extend from the base 13 a to the one end 13 b of the resin case 13 . The first bus bar 3 A is formed in a plate shape and is then bent by sheet-metal working or pressing so as to be disposed along the upper face 13 aa of the base 13 a , the upright face 13 ba of the one end 13 b , and the top face 13 bb of the one end 13 b . Specifically, the first bus bar 3 A is formed by continuously disposing: a connection portion 3 Aa connected to the relay 2 along the upper face 13 aa of the base 13 a ; an intermediate portion 3 Ab along the upright face 13 ba of the one end 13 b ; and a connection portion 3 Ac connected to the wiring member W along the top face 13 bb of the one end 13 b . The connection portion 3 Ac is disposed in the cutout 13 bc of the one end 13 b and is formed with a screw hole 3 Ad for fixing and conductively connecting one wiring member W.

The second bus bar 3 B is provided to extend from the base 13 a to the other end 13 c of the resin case 13 . The second bus bar 3 B is formed in a plate shape and is then bent by sheet-metal working or pressing so as to be disposed along the upper face 13 aa of the base 13 a , the slope 13 ca of the other end 13 c , and the top face 13 cb of the other end 13 c . Specifically, the second bus bar 3 B is formed by continuously disposing: a connection portion 3 Ba connected to the relay 2 along the upper face 13 aa of the base 13 a ; an intermediate portion 3 Bb along the slope 13 ca of the other end 13 c ; and a connection portion 3 Bc connected to the wiring member W along the top face 13 cb of the other end 13 c . The connection portion 3 Bc is disposed in the cutout 13 cc of the other end 13 c and is formed with a screw hole 3 Bd for fixing and conductively connecting the other wiring member W. As illustrated in FIGS. 2 and 5 , in the present embodiment, the second bus bar 3 B has a width dimension W 3 B in the width direction Y formed to be the same as a width dimension W 3 A of the first bus bar 3 A in the width direction Y.

The heat transfer member 4 of the cooling unit 12 has insulating properties. As illustrated in FIGS. 1 to 5 , the heat transfer member 4 includes a first heat transfer member 4 A in contact with the first bus bar 3 A and a second heat transfer member 4 B in contact with the second bus bar 3 B.

The first heat transfer member 4 A is provided to extend from the base 13 a to the one end 13 b of the resin case 13 . The first heat transfer member 4 A is formed in a plate shape so as to overlap the first bus bar 3 A, and is then bent along the connection portion 3 Aa and the intermediate portion 3 Ab. Specifically, the first heat transfer member 4 A is formed by continuously disposing: a flat portion 4 Aa overlapping and being in contact with the connection portion 3 Aa; and a rising portion 4 Ab overlapping and being in contact with the intermediate portion 3 Ab. With respect to the resin case 13 , the first heat transfer member 4 A is disposed to be embedded in the base 13 a such that the plate face of the flat portion 4 Aa is flush with the upper face 13 aa of the base 13 a and to be embedded in the one end 13 b such that the plate face of the rising portion 4 Ab is flush with the upright face 13 ba of the one end 13 b . Each plate face of the first heat transfer member 4 A faces and comes into contact with the plate face of the first bus bar 3 A. As illustrated in FIGS. 2 and 5 , in the present embodiment, the first heat transfer member 4 A has a width dimension W 4 A in the width direction Y formed to be greater than the width dimension W 3 A of the first bus bar 3 A in the width direction Y.

The first heat transfer member 4 A includes cutouts 4 Ae formed at ends thereof in the width direction Y. The cutouts 4 Ae are provided to oppose to each other in the width direction Y. The cutouts 4 Ae are provided in the rising portion 4 Ab of the first heat transfer member 4 A. The first heat transfer member 4 A is formed such that the width dimension W 4 A in the width direction Y is narrowed to a width dimension W 4 A′ by the opposing cutouts 4 Ae. The width dimension W 4 A′ of the first heat transfer member 4 A narrowed by the cutouts 4 Ae is smaller than the width dimension W 3 A of the first bus bar 3 A in the width direction Y. A resin member 13 e of the resin case 13 is inserted and fitted into the cutouts 4 Ae. The resin member 13 e fitted into the cutouts 4 Ae comes into contact with the plate face of the first bus bar 3 A because the width dimension W 4 A′ of the first heat transfer member 4 A narrowed by the cutouts 4 Ae is smaller than the width dimension W 3 A of the first bus bar 3 A in the width direction Y.

The second heat transfer member 4 B is provided to extend from the base 13 a to the other end 13 c of the resin case 13 . The second heat transfer member 4 B is formed in a plate shape so as to overlap the second bus bar 3 B, and is then bent along the connection portion 3 Ba and the intermediate portion 3 Bb. Specifically, the second heat transfer member 4 B is formed by continuously disposing: a flat portion 4 Ba overlapping and being in contact with the connection portion 3 Ba; and an inclined portion 4 Bb overlapping and being in contact with the intermediate portion 3 Bb. With respect to the resin case 13 , the second heat transfer member 4 B is disposed to be embedded in the base 13 a such that the plate face of the flat portion 4 Ba is flush with the upper face 13 aa of the base 13 a and to be embedded in the other end 13 c such that the plate face of the inclined portion 4 Bb is flush with the slope 13 ca of the other end 13 c . Each plate face of the second heat transfer member 4 B faces and comes into contact with the plate face of the second bus bar 3 B. As illustrated in FIGS. 2 and 5 , in the present embodiment, the second heat transfer member 4 B has a width dimension W 4 B in the width direction Y formed to be greater than the width dimension W 3 B of the second bus bar 3 B in the width direction Y.

The second heat transfer member 4 B includes cutouts 4 Be formed at ends thereof in the width direction Y. The cutouts 4 Be are provided to oppose to each other in the width direction Y. The cutouts 4 Be are provided in the flat portion 4 Ba and the inclined portion 4 Bb of the second heat transfer member 4 B. The second heat transfer member 4 B is formed such that the width dimension W 4 B in the width direction Y is narrowed to a width dimension W 4 B′ by the opposing cutouts 4 Be. The width dimension W 4 B′ of the second heat transfer member 4 B narrowed by the cutouts 4 Be is smaller than the width dimension W 3 B of the second bus bar 3 B in the width direction Y. In addition, the resin member 13 e of the resin case 13 is inserted and fitted into the cutouts 4 Be. The resin member 13 e fitted into the cutouts 4 Be comes into contact with the plate face of the second bus bar 3 B because the width dimension W 4 B′ of the second heat transfer member 4 B narrowed by the cutouts 4 Be is smaller than the width dimension W 3 B of the second bus bar 3 B in the width direction Y.

As illustrated in FIGS. 2 to 5 , the metal plate 5 of the cooling unit 12 is formed in a plate shape so as to overlap the heat transfer member 4 , and is then bent by sheet-metal working or pressing. The metal plate 5 is in contact with the plate face of the heat transfer member 4 . Specifically, the metal plate 5 is formed by continuously disposing: a flat portion 5 a along the flat portion 4 Aa of the first heat transfer member 4 A and the flat portion 4 Ba of the second heat transfer member 4 B; a rising portion 5 b along the rising portion 4 Ab of the first heat transfer member 4 A; and an inclined portion 5 c along the inclined portion 4 Bb of the second heat transfer member 4 B. The metal plate 5 includes a flexure 5 f formed away from the heat transfer member 4 at a boundary between the first heat transfer member 4 A and the second heat transfer member 4 B. As illustrated in FIGS. 2 and 5 , in the present embodiment, the metal plate 5 has a width dimension W 5 in the width direction Y formed to be the same as the width dimensions W 4 A and W 4 B of the heat transfer member 4 in the width direction Y.

Therefore, the metal plate 5 is formed in a shape conforming to the shape of the bus bar 3 (the first bus bar 3 A and the second bus bar 3 B) as the heat generating component 11 via the heat transfer member 4 (the first heat transfer member 4 A and the second heat transfer member 4 B). The heat transfer member 4 (the first heat transfer member 4 A and the second heat transfer member 4 B) intervenes between the bus bar 3 (the first bus bar 3 A and the second bus bar 3 B) as the heat generating component 11 and the metal plate 5 .

The metal plate 5 includes cutouts 5 e formed at ends thereof in the width direction Y. The cutouts 5 e are formed in the same arrangement and the same shape so as to overlap and match the cutouts 4 Ae and 4 Be of the heat transfer member 4 in the height direction Z. The cutouts 5 e are provided to oppose to each other in the width direction Y. The metal plate 5 is formed such that the width dimension W 5 in the width direction Y is narrowed to a width dimension W 5 ′ by the opposing cutouts 5 e . The width dimension W 5 ′ of the metal plate 5 narrowed by the cutouts 5 e is the same as the narrowed width dimensions W 4 A′ and W 4 B′ of the heat transfer member 4 and is smaller than the width dimensions W 3 A and W 3 B of the bus bar 3 in the width direction Y. The resin member 13 e of the resin case 13 is inserted and fitted into the cutouts 5 e . The resin member 13 e fitted into the cutouts 5 e comes into contact with the plate face of the bus bar 3 because the width dimension W 5 ′ of the metal plate 5 narrowed by the cutouts 5 e is smaller than the width dimensions W 3 A and W 3 B of the bus bar 3 in the width direction Y.

As illustrated in FIGS. 1 to 5 , the metal pipe 6 of the cooling unit 12 is formed in a tubular shape and includes a base 6 a and connection ends 6 b and 6 c at both ends of the base 6 a.

The base 6 a is provided to extend mainly along the length direction X, is disposed along the metal plate 5 , and is disposed on an opposite side of the positions of the bus bar 3 (the first bus bar 3 A and the second bus bar 3 B) in an opposing manner. Specifically, as illustrated in FIG. 4 , the base 6 a is bent along the flat portion 5 a , the rising portion 5 b , and the inclined portion 5 c of the metal plate 5 . The base 6 a is embedded inside the resin case 13 . The base 6 a is formed with a flat surface portion 6 d opposing to and being in contact with the plate face of the metal plate 5 . The flat surface portion 6 d may be provided on at least one face opposing to the plate face of the metal plate 5 and may be provided on another face. The metal pipe 6 includes a flexure 6 f formed away from the metal plate 5 at a boundary between the first heat transfer member 4 A and the second heat transfer member 4 B. As illustrated in FIGS. 2 and 5 , in the present embodiment, the metal pipe 6 (the base 6 a ) has a width dimension W 6 in the width direction Y formed to be smaller than the width dimensions W 4 A and W 4 B of the heat transfer member 4 in the width direction Y and than the width dimension W 5 of the metal plate 5 .

The connection ends 6 b and 6 c are formed to be bent in the width direction Y from the respective ends of the base 6 a and to extend to the outside of the resin case 13 . Although not clearly illustrated in the drawing, the connection ends 6 b and 6 c are connected to a coolant flow path that supplies a coolant to one of the connection ends 6 b and 6 c and recovers the coolant from the other of the connection ends 6 b and 6 c . Therefore, the coolant flows through the metal pipe 6 . Examples of the coolant include air, water, and antifreeze (long life coolant: LLC).

As described above, the electrical junction box 10 of the embodiment includes: the heat generating component 11 , the cooling unit 12 that cools the heat generating component 11 , and the resin case 13 that holds the heat generating component 11 and the cooling unit 12 . The cooling unit 12 includes: the metal plate 5 being formed in a shape conforming to the shape of the bus bar 3 of the heat generating component 11 ; the metal pipe 6 that is disposed along and in contact with the metal plate 5 and through which the coolant flows; and the heat transfer member 4 having insulating properties and intervening between the heat generating component 11 and the metal plate 5 .

The wire harness WH of the embodiment includes the wiring member W having electrical conductivity, and the electrical junction box 10 being electrically connected to the wiring member W. The electrical junction box 10 includes the heat generating component 11 , the cooling unit 12 that cools the heat generating component 11 , and the resin case 13 that holds the heat generating component 11 and the cooling unit 12 . The cooling unit 12 includes: the metal plate 5 being formed in a shape conforming to the shape of the bus bar 3 of the heat generating component 11 ; the metal pipe 6 that is disposed along and in contact with the metal plate 5 and through which the coolant flows; and the heat transfer member 4 having insulating properties and intervening between the heat generating component 11 and the metal plate 5 .

According to the electrical junction box 10 and the wire harness WH, the heat generated by the heat generating component 11 is transferred to the metal plate 5 having a shape conforming to the shape of the bus bar 3 of the heat generating component 11 and is cooled by the coolant flowing through the metal pipe 6 in contact with the metal plate 5 . According to the electrical junction box 10 and the wire harness WH, heat is transferred from the heat generating component 11 to the metal plate 5 while insulating properties are provided by the heat transfer member 4 between the heat generating component 11 and the metal plate 5 . Therefore, the electrical junction box 10 and the wire harness WH of the embodiment can improve the cooling performance while achieving reduction in size and weight without increasing the volume of the metal plate 5 .

In the electrical junction box 10 and the wire harness WH of the embodiment, the cooling unit 12 includes the cutouts 4 Ae and 4 Be in the heat transfer member 4 , and the resin case 13 includes the resin member 13 e fitted into the cutouts 4 Ae and 4 Be of the heat transfer member 4 and provided in contact with the bus bar 3 of the heat generating component 11 .

According to the electrical junction box 10 and the wire harness WH, the resin member 13 e of the resin case 13 is fitted into the cutouts 4 Ae and 4 Be of the heat transfer member 4 and comes into contact with the bus bar 3 of the heat generating component 11 , so that the amount of compression of the heat transfer member 4 in the plate thickness direction (height direction Z) is maintained. Therefore, an insulation distance between the metal plate 5 and the heat generating component 11 can be maintained.

In the electrical junction box 10 and the wire harness WH of the embodiment, the cooling unit 12 includes the cutouts 5 e matching the cutouts 4 Ae and 4 Be of the heat transfer member 4 in the metal plate 5 , and the resin case 13 includes the resin member 13 e also fitted into the cutouts 5 e of the metal plate 5 .

According to the electrical junction box 10 and the wire harness WH, the provision of the cutouts 5 e matching the cutouts 4 Ae and 4 Be of the heat transfer member 4 in the metal plate 5 enables the cutouts 4 Ae and 4 Be and the cutouts 5 e to be processed together by overlapping the heat transfer member 4 and the metal plate 5 . Therefore, manufacturing can be facilitated. Moreover, according to the electrical junction box 10 , by fitting the resin member 13 e also into the cutouts 5 e of the metal plate 5 , the position of the metal plate 5 in the width direction Y and the length direction X can be regulated.

In the electrical junction box 10 and the wire harness WH of the embodiment, the metal pipe 6 includes the flat surface portion 6 d that opposes to the plate face of the metal plate 5 and is in contact with the plate face of the metal plate 5 .

According to the electrical junction box 10 and the wire harness WH, the contact area between the metal plate 5 and the metal pipe 6 can be increased by the flat surface portion 6 d opposed to and in contact with the plate face of the metal plate 5 to improve the heat conductivity, and the cooling performance can be improved.

Note that the above-described electrical junction box 10 and wire harness WH according to the embodiment of the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope recited in the claims. The electrical junction box 10 and wire harness WH according to the present embodiment may be configured by appropriately combining the constituent elements of the embodiment and the modifications described above.

The electrical junction box and the wire harness according to the present embodiment can appropriately have cooling performance.

Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth.